GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Arberella flaccida

HABIT Perennial; caespitose. Culms geniculately ascending; 15–27 cm long; 3–4 -noded. Culm-internodes solid. Culm-nodes constricted. Lateral branches lacking. Leaves cauline; 5–8 per branch. Leaf-sheaths ribbed. Ligule a ciliolate membrane; 0.4–0.6 mm long; truncate. Leaf-blade base asymmetrical; with a brief petiole-like connection to sheath; petiole 0.1 cm long; petiole glabrous. Leaf-blades lanceolate, or ovate; 4–5 cm long; 8–10 mm wide. Leaf-blade surface glabrous. Leaf-blade margins ciliate. Leaf-blade apex acute.

INFLORESCENCE Monoecious; with male and female spikelets in the same inflorescence (or some all male). Inflorescence a panicle; comprising 1 fertile spikelets (and 5–8 male); terminal and axillary. Axillary inflorescences present throughout the plant.

Panicle open; linear; 4–5 cm long; bearing few spikelets.

Sexes segregated; on unisexual branches; with male below. Spikelets solitary. Fertile spikelets pedicelled. Male spikelets pedicelled; 1–2 in a cluster. Pedicels clavate (female), or linear (male).

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or obovate; dorsally compressed; 8.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; truncate.

GLUMES Glumes deciduous; similar; exceeding apex of florets; thinner than fertile lemma; incurved at apex. Lower glume elliptic; 8.5 mm long; 1.05 length of upper glume; membranous; pallid; without keels; 5–6 -veined. Lower glume lateral veins with cross-veins. Lower glume apex attenuate. Upper glume elliptic; 8 mm long; 1.6 length of adjacent fertile lemma; membranous; pallid; without keels; 5–6 -veined. Upper glume lateral veins with cross-veins. Upper glume apex attenuate.

FLORETS Fertile florets female. Fertile lemma elliptic, or ovate; dorsally compressed; 5 mm long; indurate; pallid; shiny; without keel; 5 -veined. Lemma lateral veins with cross-veins. Lemma surface pubescent; hairy at base. Lemma margins pubescent. Lemma apex acute. Palea indurate.

FLOWER Lodicules 3; 0.5 mm long; membranous. Anthers 3; 1.8–2 mm long. Stigmas 2.

MALE Male spikelets distinct from female; 1 flowered; linear, or lanceolate; 3.7–4 mm long. Male spikelet glumes absent. Male spikelet lemma 5 -veined.

DISTRIBUTION South America: northern South America and Brazil.

NOTES Olyreae. Soderstrom.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.